Can anyone point to a Producer Letter, dev, or rep post that clearly explains the Optimal Rank system? Can someone post a link if such a post exists?

And is the detriment to stats clearly shown IN-GAME, where it is most important? Red numbers, red arrows, red symbols... red something! It would be nice to see the Optimal stats next to the stats you actually are receiving for comparison or implement a "not-Optimal icon" so players are aware their gear is out of rank range.